Codec Compatibility Test
Map video, audio and container support with instant checks plus real playback proof.
Private by design: detection calls browser APIs only, and the real playback test generates its own tiny samples on this device. Nothing is downloaded from or uploaded to any server.
Nothing checked yet. Instant detection reads support tables without downloading samples.
Map codec support in two minutes
- Press Run instant detection: the page asks the browser about 15 formats via canPlayType and MediaCapabilities.
- Read the table: Supported, Probably, Declared-but-untested, or Not supported — plus smooth and power flags when reported.
- Press Test real audio playback: a tiny tone is generated locally and must play end to end.
- Press Test real video playback: a two-second clip is recorded from a generated animation and played back.
- Real playback overrides the tables: Plays or Fails is proof, the rest is declaration.
- Copy the results when reporting a playback bug to a developer.
Codec test questions
Why does HEVC show as untested even on new devices?
Browsers often answer an empty string for HEVC while the OS plays it fine. The real video test is the only in-browser proof — declarations alone mislead.
What is the difference between Probably and Supported?
Probably means the browser answered maybe: the container parses, but success is not promised. Supported means it answered probably — the strongest declaration the API gives.
Does this test download sample files?
No. Instant detection downloads nothing, and the real test synthesizes its own tone and clip on this device. That keeps the page light and private.
A format plays elsewhere but fails here. Why?
Site data, extensions, hardware-acceleration flags and enterprise policies change per-browser behavior. Retest in a clean profile before blaming the file.